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INHERITANCE OF HAY FEVER. A PRELIMINARY REPORT·
RAY M. BALYEAT AND MIWRED HOGE RICHARDS·
WHEN THE family histories of patients suffering from hay fever are studied, it is at once evident that, in a majority of cases, other members of the
family are similarly affected. In some families, different individuals show
different forms of sensitivity. Thus the sensitivity may tak~ the form of
hay fever, bronchitis, asthma, eczema, urticaria (hives), or migraine
{sick headaches). In many cases, all the members of a sensitive family sufter
from either asthma or hay fever and, in half the cases studied, the senSItivity is nearly specific for one family.
To determine how the inheritance of hay fever and these allied forms of
~llergy takes place, a preliminary study was made of twelve families each
d which includes one or more patients treated by one of the authors
(Balyeat). The histories of these families were obtained from answers to
carefully prepared questions. As the patients are of a highly intelligent
class, the accuracy of the histories is perhaps greater than may usually be
('xpected in studies of human inheritance.
_$ince hay fever and other forms of allergy are obviously inherited, and
since the transmission may go from father to child, it is obvious that the
ir.JbtriJ~tl~_':llust be through the germ cells. The next point to determine
i1' the exact way in which the character is inherited. Does it act as an
(lrdinary Mendelian character and is it dominant or recessive?
Miss June Adkinson (Genetics 1920) has studied a number of histories
of a similar nature and considers bronchial asthma to be a recessive character. After a very preliminary study of their histories, the authors conclude
that hay fever is not a recessive character. We have a number of cases
showing that, after a marriage between an affected individual and a normal person from a negative family, affected children are born. Miss Adkinson would have to consider that in such cases, the normal person was
heterozygous. However, if the family history for several generations has
~hown no cases of allergy, it seems more reasonable to consider normal
individuals from such families as unaffected. Family 1 is such a case, for 10
two cases in this family after a marriage between a normal negative ind.vidual and a hay fever sufferer, affected children resulted.
In addition to these cases which show that hay fever may act as a
dominant, there are cases, even more frequent, which show that hay fever
may skip' a generation. Hay fever individuals then result from a marriage
hetween two normal individuals, but always one parent is from an affected
{amily. Family 2 contains a number of matin~s of this nature. As this
family history is typical, complete and also reliable, only two charts are
included in this paper.
~usly hay fever is not a complete dominant and the ven_e fer sen,sitivity. may o~~-~ay -not produce abnormality. This incomplete dominanCe
has its counterpart in cases among animals and plants. In many of these
C3Sa, as in heterozygous barred eyes in Drosophila and in pink four
-'n part. Contribution from the Zoological Laboratory of the University of Oklahoma.
Second Series, No. 98.
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UNIVERSITY OF OKLAHOMA BULLETIN-
o'clocks, the hybrid is intermediate between the two parents instead of
like either one parent or the other.
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FIGURE 1
The personal history of cases of hay fever and other forms of allergy
reveals another interesting fact which may explain the incomplete dominance__Ihe time of appearance of the sensitivi~y in the.-omegeny ·oL!h.e
individual differs greatly in different people. In some cases a child develops
c1 sensitivity very shortly after birth and in other cases individuals whohave never before had trouble develop a sensitivity at the age of seventy ~
Between these two extremes are a· whole series of ages, at any of which a
sensitivity may develop. Consequently, if an individ~J>elongs to. an
affected family, although he may have had no trouble, there is still- a great
probili~ that he may later develop it. Thus no chart of an affected family
can ·ever,' be considered as complete, for those once classed as normal may
later develop some form of allergy.
Another point must also be considered. In..~loC~~IJorm ofsensi,tivityto~rne ma_~i~s~Jh~~_~t. be, in additiont~~_~~itiv1ij;~~­
external fac-to!" -tnat- causes the trouble.-Kcliild -sensitive to certaulronns of -
THE ACADEMY OF SCIENCE
FIGURE 2
3J
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UNIVERSITY OF OKLAHOMA BULLETiN
protein will not develop urticaria or eczema unless he eats that protein.
Similarly an individual sensitive to a certain kind of pollen develops hay
fever only when exposed to that pollen. In recent years much has been
added to our knowledge of the interaction of heredity and environmnt.
Apparently the study of inheritance of hay fever, etc., reveals another case
in which a definite environment as well as a definite inheritance is necessary
to produce a definite character.
Since an individual who has one form of sensitivity often develops some
other form as well, it seems likely that there may be only one factor concerned. However, since some of the families studied show only one typeas hay fever, there is open the possibility of modifying factors which would
alter the type of sensitivity. Our numbers at present do not justify us in
making any definite conclusion with respect to the number of genes concerned.
Our conclusion is that hay fever is an incompletely dominant character
dependin~ partly on the environment for its fulfillment.